<template>
    <span class="v-page-pager">
        <li @click.stop.prevent="jumpPage(1)" :class='[pageIndex === 1 ? "v-page-li-active":"","v-page-li"]'>
            <a>1</a>
        </li>

        <li @click.stop.prevent="jumpPage(pageIndex - showPagingCount)" v-if="showJumpPrev" :class="[pageIndex=== 1 ? 'disabled' :'','v-page-li','v-page-jump-prev']" :title="'向前 '+showPagingCount+' 页'">
            <a>
                <i class="dbm d-icon-arrow-double-left-o"></i>
            </a>
        </li>

        <li v-for="num in pagingCounts" @click.stop.prevent="jumpPage(num)" :class='[num === pageIndex ? "v-page-li-active":"","v-page-li"]'>
            <a>{{num}}</a>
        </li>

        <li @click.stop.prevent="jumpPage(pageIndex + showPagingCount)" v-if="showJumpNext" class="v-page-li v-page-jump-next" :title="'向后 '+showPagingCount+' 页'">
            <a>
                <i class="dbm d-icon-arrow-double-right-o"></i>
            </a>

            <li v-if="pageCount >1" @click.stop.prevent="jumpPage(pageCount)" :class='[pageIndex === pageCount ? "v-page-li-active":"","v-page-li"]'>
                <a>{{pageCount}}</a>
            </li>
    </span>
</template>

<script>
export default {
  props: {
    pageCount: Number,
    pageIndex: Number,
    showPagingCount: Number
  },
  computed: {
    numOffset() {
      return Math.floor((this.showPagingCount + 2) / 2) - 1;
    },

    showJumpPrev() {
      if (this.pageCount > this.showPagingCount + 2) {
        if (this.pageIndex > this.showPagingCount) {
          return true;
        }
      }
      return false;
    },

    showJumpNext() {
      if (this.pageCount > this.showPagingCount + 2) {
        //if (this.pageIndex < this.pageCount - this.numOffset) {
        if (this.pageIndex <= this.pageCount - this.showPagingCount) {
          return true;
        }
      }
      return false;
    },

    // 当前要显示的数字按钮集合
    pagingCounts() {
      let vm = this,
        startNum,
        result = [],
        showJumpPrev = vm.showJumpPrev,
        showJumpNext = vm.showJumpNext;

      if (showJumpPrev && !showJumpNext) {
        startNum = vm.pageCount - vm.showPagingCount;
        for (let i = startNum; i < vm.pageCount; i++) {
          result.push(i);
        }
      } else if (!showJumpPrev && showJumpNext) {
        for (let i = 2; i < vm.showPagingCount + 2; i++) {
          result.push(i);
        }
      } else if (showJumpPrev && showJumpNext) {
        for (
          let i = vm.pageIndex - vm.numOffset;
          i <= vm.pageIndex + vm.numOffset;
          i++
        ) {
          result.push(i);
        }
      } else {
        for (let i = 2; i < vm.pageCount; i++) {
          result.push(i);
        }
      }

      return result;
    }
  },
  methods: {
    jumpPage(pageIndex) {
      this.$emit("jumpPageHandler", pageIndex);
    }
  },
  created() {}
};
</script>